Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E04DFC74A5B for ; Tue, 21 Mar 2023 07:40:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229865AbjCUHk6 (ORCPT ); Tue, 21 Mar 2023 03:40:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229627AbjCUHkz (ORCPT ); Tue, 21 Mar 2023 03:40:55 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A2D83B64B for ; Tue, 21 Mar 2023 00:40:42 -0700 (PDT) Received: from dggpemm500014.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Pgk325l0PznYR6; Tue, 21 Mar 2023 15:37:34 +0800 (CST) Received: from localhost.localdomain (10.175.112.125) by dggpemm500014.china.huawei.com (7.185.36.153) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Tue, 21 Mar 2023 15:40:40 +0800 From: Wupeng Ma To: , CC: , , , , Subject: [PATCH v5 1/4] mm/mlock: return EINVAL if len overflows for mlock/munlock Date: Tue, 21 Mar 2023 15:40:32 +0800 Message-ID: <20230321074035.1526157-2-mawupeng1@huawei.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230321074035.1526157-1-mawupeng1@huawei.com> References: <20230321074035.1526157-1-mawupeng1@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500014.china.huawei.com (7.185.36.153) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ma Wupeng While testing mlock, we have a problem if the len of mlock is ULONG_MAX. The return value of mlock is zero. But nothing will be locked since the len in do_mlock overflows to zero due to the following code in mlock: len = PAGE_ALIGN(len + (offset_in_page(start))); The same problem happens in munlock. Add new check and return -EINVAL to fix this overflowing scenarios since they are absolutely wrong. Return 0 early to avoid burn a bunch of cpu cycles if len == 0. Signed-off-by: Ma Wupeng --- mm/mlock.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/mm/mlock.c b/mm/mlock.c index 617469fce96d..247ce396bb16 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -479,8 +479,6 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, end = start + len; if (end < start) return -EINVAL; - if (end == start) - return 0; vma = vma_iter_load(&vmi); if (!vma) return -ENOMEM; @@ -574,7 +572,13 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla if (!can_do_mlock()) return -EPERM; + if (!len) + return 0; + len = PAGE_ALIGN(len + (offset_in_page(start))); + if (!len) + return -EINVAL; + start &= PAGE_MASK; lock_limit = rlimit(RLIMIT_MEMLOCK); @@ -634,7 +638,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) start = untagged_addr(start); + if (!len) + return 0; + len = PAGE_ALIGN(len + (offset_in_page(start))); + if (!len) + return -EINVAL; + start &= PAGE_MASK; if (mmap_write_lock_killable(current->mm)) -- 2.25.1